Optical amplifier system for pulsed laser based on a guiding gain medium and pulsed laser comprising same

An optical amplifier system 20 for pulsed laser with short or ultra-short and energetic pulses, comprising:

• an optical pumping source able to generate a pump wave 6;
• an elongate amplifying medium 3 comprising an input interface 7 able to receive an optical signal 4 to be amplified, said medium 3 being able to amplify said optical signal 4 propagating along said amplifying medium and able to extract an amplified signal 5;
• and
• an optical system 10 able to couple the pump wave 6 in the amplifying medium 3 so as to pump said amplifying medium 3 longitudinally,
• wherein:
• the amplifying medium 3 is a rotationally symmetric gain medium or a fiber able to guide said pump wave, said pump-guiding medium 3 having a minimum transverse dimension φ3 greater than 50 microns and equal to or less than 2000 microns, at the input interface 7,
• the optical system 10 is able to focus the pump wave 6 inside the gain medium 3, said focused pump wave having a transverse dimension φ6 smaller than the minimum transverse dimension φ3 and a numerical aperture smaller than the numerical aperture of the amplifying medium 3, in such a way that said pump wave propagates freely over a part 1 of the amplifying medium 3, and that said pump wave 6 propagates in a confined manner over a part 2 of the amplifying medium, by total internal reflections.